Gut microbiota is emerging as a key modulator of the immune system. Alteration of gut microbiota impacts functioning of the immune system and pathophysiology of several diseases, including cancer. Growing evidence indicates that gut microbiota is not only involved in carcinogenesis but also has an impact on the efficacy and toxicity of cancer therapy. Recently, several pre-clinical and clinical studies across diverse cancer types reported the influence of gut microbiota on the host immune response to immunotherapy. Advancement in our understanding of the mechanism behind microbiota-mediated modulation of immune response is paramount for their utilization as cancer therapeutics. These microbial therapies in combination with conventional immunotherapeutic methods have the potential to transform the pre-existing treatment strategies to personalized cancer therapy. In this review, we have summarized the current status of research in the field and discussed the role of microbiota as an immune system modulator in context of cancer and their impact on immunotherapy.

肠道微生物群正在成为免疫系统的关键调节剂。肠道菌群的改变会影响免疫系统的功能和包括癌症在内的多种疾病的病理生理学。越来越多的证据表明，肠道微生物群不仅与致癌作用有关，而且对癌症治疗的疗效和毒性也有影响。最近，几项针对不同癌症类型的临床前和临床研究报告了肠道微生物群对宿主对免疫治疗的免疫反应的影响。我们对微生物群介导的免疫反应调节背后机制的理解的进步对于它们作为癌症治疗剂的应用至关重要。这些微生物疗法与传统的免疫治疗方法相结合，有可能将现有的治疗策略转变为个性化的癌症治疗。在这篇综述中，我们总结了该领域的研究现状，并讨论了微生物群作为免疫系统调节剂在癌症背景下的作用及其对免疫治疗的影响。